libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_until.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // UNSUPPORTED: no-threads
  10 // UNSUPPORTED: c++03, c++11
  11
  12 // ALLOW_RETRIES: 2
  13
  14 // UNSUPPORTED: availability-shared_mutex-missing
  15
  16 // <shared_mutex>
  17
  18 // class shared_timed_mutex;
  19
  20 // template <class Clock, class Duration>
  21 //     bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);
  22
  23 #include <shared_mutex>
  24 #include <thread>
  25 #include <cstdlib>
  26 #include <cassert>
  27 #include <chrono>
  28
  29 #include "make_test_thread.h"
  30 #include "test_macros.h"
  31
  32 std::shared_timed_mutex m;
  33
  34 typedef std::chrono::steady_clock Clock;
  35 typedef Clock::time_point time_point;
  36 typedef Clock::duration duration;
  37 typedef std::chrono::milliseconds ms;
  38 typedef std::chrono::nanoseconds ns;
  39
  40
  41 ms WaitTime = ms(250);
  42
  43 // Thread sanitizer causes more overhead and will sometimes cause this test
  44 // to fail. To prevent this we give Thread sanitizer more time to complete the
  45 // test.
  46 #if !defined(TEST_IS_EXECUTED_IN_A_SLOW_ENVIRONMENT)
  47 ms Tolerance = ms(50);
  48 #else
  49 ms Tolerance = ms(50 * 5);
  50 #endif
  51
  52 void f1()
  53 {
  54     time_point t0 = Clock::now();
  55     assert(m.try_lock_until(Clock::now() + WaitTime + Tolerance) == true);
  56     time_point t1 = Clock::now();
  57     m.unlock();
  58     ns d = t1 - t0 - WaitTime;
  59     assert(d < Tolerance);  // within tolerance
  60 }
  61
  62 void f2()
  63 {
  64     time_point t0 = Clock::now();
  65     assert(m.try_lock_until(Clock::now() + WaitTime) == false);
  66     time_point t1 = Clock::now();
  67     ns d = t1 - t0 - WaitTime;
  68     assert(d < Tolerance);  // within tolerance
  69 }
  70
  71 int main(int, char**)
  72 {
  73     {
  74         m.lock();
  75         std::thread t = support::make_test_thread(f1);
  76         std::this_thread::sleep_for(WaitTime);
  77         m.unlock();
  78         t.join();
  79     }
  80     {
  81         m.lock();
  82         std::thread t = support::make_test_thread(f2);
  83         std::this_thread::sleep_for(WaitTime + Tolerance);
  84         m.unlock();
  85         t.join();
  86     }
  87
  88   return 0;
  89 }